Muscle-Bound Bots Bench 80 Times Their Own Weight

We've told you about an electronic skin for robots that's sensitive to touch, made of a sensor network mounted on flexible plastic. We've also told you about some admittedly creepy genetically engineered skeletal muscles for robots. A different approach to robotic muscles based on an electroactivated polymer (EAP) produces muscles that lift 80 times their own weight, a new benchmark.

Devised by a team at the National University of Singapore’s (NUS) Faculty of Engineering, the artificial muscles not only could make robots stronger, but also help them become self-powering after a brief period of charging. That's because the muscles also convert and store energy.

An electroactivated polymer (EAP) produces robotic muscles that lift 80 times their own weight. They also store energy that robots can use to operate themselves. The artificial muscle expands 5.5 times its original length while carrying a load in the form of Perspex blocks. (Source: National University of Singapore)

The Perspex blocks lifted by the artificial muscle weigh 231 gm (left), more than 80 times the weight of the electroactivated polymer (EAP) muscle (right) at 2.77 gm. (Source: National University of Singapore)

Like organic muscles in people or animals, robotic muscles based on EAPs respond to electrical stimulation. The NUS team's materials respond very quickly to electrical impulses, said team leader Adrian Koh, from the university's engineering science programme and the department of civil and environmental engineering, in a press release:

Our materials mimic those of the human muscle, responding quickly to electrical impulses, instead of slowly for mechanisms driven by hydraulics. Robots move in a jerky manner because of this mechanism. Now, imagine artificial muscles which are pliable, extendable, and react in a fraction of a second like those of a human. Robots equipped with such muscles will be able to function in a more human-like manner -- and outperform humans in strength.

Koh said that the artificial muscles' ability to lift 80 times their own weight is a first in robotics. So far the limit has been lifting about half their own weight, much like the limit of the average human. Previous artificial muscles could stretch only three times their length. But while carrying these loads, the new muscle material can be stretched to about five times its original length, also a first. When Koh and his team began their research last year, they calculated that EAPs could theoretically be stretched over 10 times their original length and lift a load up to 500 times their own weight.

The materials produce electrical energy converted from mechanical energy as they expand and contract, said Koh. In fact, quite a lot of it. "We calculated that if one were to build an electrical generator from these soft materials, a 10kg system is capable of producing the same amount of energy of a 1-ton electrical turbine" he said. After less than a minute of charging, a robot could thus be self-powered.

In June, Koh was awarded the Promising International Researcher Award at EuroEAP 2013, the third international conference on Electromechanically Active Polymer transducers & artificial muscles in Zurich, Switzerland. The team also presented some of its findings at the conference in a paper, "Dielectric elastomer generators: from fundamentals to realization."

Wow, Ann, this is pretty impressive. This type of strength and capability of robots has a lot of potential for application, and really shows how advanced robot functionality is becoming. I could see this being used in artificial limbs or muscles, which would be an amazing breakthrough for the human users. It reminds me of the bionic man television show back in the 1980s (if I may date myself here, ahem...or was it the 70s? sometimes I get confused).

The Army also is working on a futuristic "Iron Man" type exoskeleton suit for soldiers...perhaps this type of thing could have an application there: http://siliconangle.com/blog/2013/10/14/us-army-building-talos-real-life-ironman-armor-to-give-troops-superhuman-strength/

Wow, these are amazing numbers, Ann. They've improved their lifting ability by a factor of 160X, while tripling their stroke length. I would expect the lifting ability to increase when the stroke length is shorter.

Yes, Chuck, this is one of the most amazing materials discoveries I've seen. It's all in the plastic. The relationship you expect between strength (lifting ability) and stroke length might be true, within limits, for other materials such as metals.

And thanks for the TV history check, Ann! I guess I could've done that myself. I thought it was the 70s...it would be interesting to do a retrospective now and see what technology the bionic man supposedly had and compare it to technology actually available today. Maybe some would match up!

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